Yes, there's a comic strip with librarians as the main characters. Unshelved is actually a blog with a comic strip that changes daily—three-panel, black-and-white strips from Monday to Saturday, and special, colored strips on Sundays.

You can check out its archives, or the primer, which introduces all the regular characters, including three librarians, a 12-year-old customer, a mascot and a nudist lawyer =)